Actuating mechanism for hoisting machine



Jan. 29, 1963 s. T. BUCK 3,075,618

ACTUATING MECHANISM FOR I-IOISTING MACHINE Filed July 22, 1960 5Sheets-Sheet 1 fi IN V EN TOR.

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Jan. 29, 1963 S. T. BUCK ACTUATING MECHANISM FOR HOISTING MACHINE FiledJuly 22, 1960 5 SheetsSheet 2 o o O 51 O INVENTOR. Srsmqzo 7. Buzz,

ATTORNEYS.

Jan. 29, 1963 s. T. BUCK 3,075,618

ACTUATING MECHANISM FOR HOISTING MACHINE Filed July 22, 1960 3Sheets-Sheet 3 s N k k 1 I 3) J I77. A Qr- I: N. z: N a; g

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BY 577. Am 7. Eve/c, flay/ ATTORN 5V5- United States Patent'O 3,075,618ACTUATING MECHANISM FOR HOISTING MACHINE Steward T. Buck, Buck EquipmentCorp, 720 Anderson Ferry Road, Cincinnati, Ohio Filed .Iuly 22, 1960,Ser. No. 44,599 11 Claims. (Cl. 187-32) This invention relates tohoisting machines of the type used on construction jobs and the like toraise supplies and equipment to the upper stories of a building or otherelevated work site. While such hoisting machines may take various forms,they usually comprise a tower provided wit-h vertically extendingguideways or tracks along which a lift platform is adapted to be moved,the lift platform being raised and lowered by means of a cable one endof which is wound on the drum of a hoist having a prime mover and clutchmechanism for selectively rotating the drum in opposite directions toraise and lower the lift platform.

In my copending application Serial No. 761,186, filed September 15,1958, and entitled Automatic Control Sys tern for Hoisting Machine, Ihave taught the provision of a hoisting machine of the general type justcharacterized which incorporates an automatic control system forstarting and stopping the lift platform at predetermined upper and lowerpositions, the machine operator having only to start the platform on itsupward or downward journey whereupon the control system, which iselectrically controlled, takes over to stop the lift platform at apre-set position. While such automatic system has proven to be highlysuccessful, the mechanism is nevertheless relatively expensive and thereis a decided need in the industry for a less expensive, preferablynon-electronic mechanism for controlling the up and down movement of thelift platform.

Accordingly, a principal object of the instant invention is theprovision of actuating and control mechanism for a hoisting machinewhich is of relatively simple and inexpensive construction and yetenables the operator to pre-set the level at which the lift platformwill be stopped, thereby relieving him for other duties.

A further object of the instant invention is the provision of actuatingand control mechanism for a hoisting machine which is positive in actionand in which mechanical means are employed to control the starting andstopping of the hoist mechanism to the elimination of the more costlyelectronic controls of the system taught in the aforementionedapplication.

The foregoing together with other objects of the invention which willappear hereinafter or which will be apparent to the skilled worker inthe art upon reading these specifications, I accomplish by thatconstruction and arrangement of parts which I shall now describe inexemplary embodiments.

Reference is now made to the figures of the drawings wherein:

FIGURE 1 is a side elevational view of a portable hoisting machine withthe tower in its elevated position.

FIGURE 2 is an enlarged fragmentary plan view of the selector disc forselectively engaging the clamps on the control cable.

FIGURE 3 is a side elevational view with certain parts shown in dottedlines of the selector disc assembly of FIGURE 2.

FIGURE 4 is a plan view of the hoist mechanism showing the clutch andbrake assembly together with its actuating means.

FIGURE 5 is an enlarged fragmentary and elevational view of the clutchand brake mechanism and the cam means for actuating them.

3,075,618 Patented Jan. 29, 1963 ICC FIGURE 6 is an enlarged sideelevational view with parts broken away of the brake shoe assembly,illustrating the manner in which it is actuated by the cam means.

FIGURE 7 is a vertical cross sectional view illustrating the generallayout of the clutch and brake mechanism.

FIGURE 8 is an enlarged side elevational view of the cam Wheel whichcontrol the position of the cam shaft and cam segments for actuating thebrake and clutch shoes.

FIGURES 9 and 10 she side elevational views of brake and clutchactuating cams.

Referring first to FIGURE 1 of the drawings, I have therein illustrateda portable hoisting machine with which the actuating mechanism of theinstant invention may be employed. Essentially, the machine comprises abase or frame 1 mounting a vertically extending tower 2 along which thelift platform or other lifting means 3 is adapted to travel, the liftplatform having grooved rollers 4 adapted to move along guide rails ortracks 5 forming a part of the tower structure. The lift platform isadapted to be raised and lowered, as from the position shown in solidlines at the bottom of the figure to the position shown in dotted linesat the top thereof, by means of a lift cable 6 which extends upwardlyfrom the hoist mechanism 7 around a pulley 8 at the top of the tower andthen downwardly for attachment to the lift platform. The base or frame 1of the device may be provided with retractable wheels 9 'by means ofwhich the device may be readily transported from place to place; and tofacilitate such transportation, the tower is preferably formed as aplurality of hinged sections joined together by means of hinges 10.Collapsible towers of this character are disclosed in my Patent No.2,653,685 dated September 29, 1953 and entitled Portable Hoisting Tower,and reference is made to the patent for details of the construction andmode of erecting and collapsing the tower structure. However, it shouldbe understood from the outset that the particular form of towerstructure does not constitute a limitation upon the instant inventionsince the actuating mechanism to be hereinafter described is applicableto diverse types of devices, whether they be of portable character orerected on the job in a piece by piece assembly.

Referring now to FIGURE 4, the base or frame 1 mounts a prime mover 11,which generally comprises an internal combustion engine the drive shaftof which is operatively connected, as by means of the chain drive 12, tothe hoist mechanism 7 which includes a drum shaft 13 to which the drum14 for the lift cable 6 is secured. The shaft 13 also mounts a clutchmechanism 15 operatively connected to the chain drive 12; and a brakemechanism 16 is also provided for locking the cable drum 14 againstrotation. If desired, the drum shaft 13 may also be provided with apower take-off 17 and/or a work head 18.

The actuating and control mechanism for the hoist comprises a cam shaft19 provided at one end with a control wheel 20 and its opposite end witha control cam 21 by means of which the cam shaft may be releasablysecured in its various positions of use. The cam shaft 19 mounts aseries of cams, which will be described in detail hereinafter, by meansof which the brake mechanism I6 is engaged and released and the clutchmechanism 15 activated to either raise or lower the lift platformdepending upon the direction of rotation of the cable drum 14.

Essentially, the cam shaft 19 has three positions of use. The firstcomprises an intermediate or neutral position in which the brakemechanism 16 is locked and both the up and down components of the clutchmechanism 15' are disengaged. From the neutral position, the cam shaftmay be rocked in either a clockwise or a counter-clockwise manner;rotation or rocking movement in one direction serving to engage the upcomponent of the clutch mechanism while at the same time releasing thebrake, whereas rocking movement in the opposite direction serves toengage the down component of the clutch mechanism and also serves torelease the brake. Rocking movement of the cam shaft is effective bymean of a control cable 22 secured to the control wheel 20.

As seen in FIGURE 1, the control cable 22 extends from control wheel 20to a pulley wheel or sheave 23 located 'at the lower end of the tower 2adjacent the lift platform 3, the cable then extending upwardly alongthe tower in close promixity to the path of travel of the lift platform,the control cable passing around one or more pulley wheels 24 at theupper end of the tower and then returning downwardly to the controlwheel 20. Preferably, the control cable 22 is in the form of an endlessband one portion of which is wrapped about a periphery of the controlwheel-which may be grooved for this purposethe cable being cleated orotherwise fixedly secured to the control wheel. With this arrangement,the control cable will have a limited movement in opposite directions,the extent of such movement being determined 'by the degree of rotativemovement required to move the cam shaft 19 from the neutral position toeither of the operating positions. It will be apparent that the controlwheel 2% may be turned so as to rock the cam shaft by engaging andpulling on the control cable at any point along its length.

Spaced along that portion of the control cable which parallels the pathof travel of the lift platform 3 are a plurality of cable clamps 25,which are of successively larger diameter, with the smallest diameterclamp 25a "lowermost and the successively larger diameter clamps 25b 25cand 25d spaced upwardly along the control cable. These clamps areadapted to be selectively engaged by a cable follower 26 mounted on thelift platform 3, the cable follower surrounding and moving along thecontrol cable as the lift platform moves up and down along the tower. Asbest seen in FIGURES 2 and 3, the cable follower 26 is provided with amounting arm 27 by means of which it may be readily secured to the liftplatform, the follower being provided with an irregular slot 28 throughwhich the control cable is adapted 'to be passed, the inner end of theslot 28 terminating in an annular opening 29 through which the severalcable clamps 25 may freely pass, with the possible exception of theuppermost cable clamp 25d. The cable follower also mounts a rotatableselector disc 30 having a pinrality of open'ings 31 therein ofsuccessively larger diameter adapted to be selectively juxtaposed to theopening 29. It will be noted that each of the openings 31a, "31b, 31cand 31d has a neck portion 32 opening outwardly to the periphery of theselector disc 30, the neck portions 32 being arranged to be aligned withthe irregu- -l-ar' slot 23 so that the control cable may be initiallyintro- 'duced-therein, whereuponthe necks 32 may be offset with respectto the slot 28, as will be clear from FIGURE 2, thereby assuringretention of the control cable within the confines of the selectedopening 31. A spring biased detent 33 is preferably provided coactingwith depressions 34 in the unde'rsurface of the disc 30 to align theseveral openingslfl with respect to the opening 29.

The diameter of the openings-31 are correlated to the diameters of thecable clamps 25 so as to pass or stop the cable clamps as the liftplatform moves along the tower with the cable follower in engagementwith the control cable.

In the embodiment illustrated there are four cable clamps and fouropenings in the selector disc. The smallest opening 31a in the selectordisc is of a diameter smaller than the diameter ofthe lowermost cablethrough the opening 31a and continued upward movement of the liftplatform will draw the cable with it, thereby causing the control wheel20 to be rotated. Such rotation acts to disengage the up component ofthe clutch and set the brake, thereby arresting the upward movement ofthe lift platform at'a predetermined elevation. It will be understood,.of course, that such predetermined elevation may be varied -byadjusting theposition of the cable clamps 25 along the control cable 22.If the lift platform is to be raised to the position established by thecable clamp 25c,'then the selector disc will be set so that the opening31c surrounds the cable. The diameter of the opening 310 is such that itwill permit the lowermost cable clamp 25a to pass freely therethrough,as will the next cable clamp 2512; but the cable clamp 250 will beengaged and retained, whereupon the cable willbe lifted to disengage theup component of the hoist mechanism.

It will be understood that the upward movement of the lift platform 3will be initiated by rocking the cam shaft 19 to clutch engagingposition. This may be done by means of a hand grip 35 secured to thereturn flight of the control cable 22 in a position where it may bereadily grasped by the machine operator. If desired, the opposite end ofthe cam shaft 19 may be provided with a second control wheel 36' whichmay be utilized to actuate the hoist mechanism from the opposite side ofthe machine. Such second'controlwheel may be provided with a crankhandle 37 and, if desired, a second control cable 22a may extendupwardly from the control wheel 36 in much the same manner as the cable22, although the sec- *ond cable need not be provided with the cableclamps 25.

From the foregoing it should be apparent that the downward movement ofthe lift platform may be controlled in similar fashion to the upwardmovement thereof by suitably adjusting-theselector disc to either passor stop the various cable clamps. The bottom or down position of thelift platform may be permanently fixed by means of a cable clamp 2512which will bed a diameter larger than any of the openings 31 in theselector disc.

As'seen in FIGURE 3, the cable clamps 25 will'prefcrably have acylindrical center portion 38 terminating in conical end portions 39 bymeans of which the clamps will be guided through the openings 29 and 31.In the case of the clamps defining'the upper and lower limits of travel,the conical portions 39v facing the openings may be eliminated since atno time do these clamps pass through the selector disc.

it is also desirable to provide the selector disc assembly with amanually controlled cable locking device to prevent accident-ailactuation of the control mechanism. To "this end, the cable follower 26may mount a block 40 to which an arm 41 is slidably secured, the armbeing movable horizontally from the position illustrated in solid linesin FIGURE '3 to-the position illustrated in dotted lines. The arm 41 isprovided with a generally V-shaped notch 42 which, whenthe armisin theextended position, receives the control cable 22 and overlies the cableclamp 25 engaged by the selector disc. The cable clamp is thuseffectively retained between the selector disc and the arm and movementof the cable is prevented. Thus, if a person loading it. The arm 41 maybe conveniently actuated by means of a' finger grip43, the arm having anelongated slot 44 therein movable relative to the studs-45 and retainedin the rettr-acted'or extended position by means of spring detent "46engageable in depressions or the like 47 in the undersurface of the arm.

Referring now to FIGURE 7 of the drawings, the clutch :mechanism 15comprisesa planetarylgear system of known character having a clutchwheel-I50 forming a partof the down component of the system, and arotatable housing 51 forming a part of the up component of the system. Aclutch band 52 surrounds the clutch wheel 56 and a similar clutch band53 surrounds the rotatable housing 51, the clutch bands acting in amanner to be fully explained hereinafter to selectively lock the clutchwheel and/or housing against rotation or free them for rotation, depend-:ing upon the direction in which the drive shaft 13 is to be driven.

The shaft 13 is driven by means of the sun gear 54 which is keyed to theshaft and positioned for engagement with the gear clusters 55 and 55aeach of which is cornposed of three gears keyed together for jointrotation about their common shafts 56 and 56a mounted in the rotatablehousing 51. An end-most gear in each cluster is in meshing engagementwith sun gear 54, whereas the intermediate gear of each cluster is inengagement with a gear head 57 secured to a rotatable sleeve 58 theopposite end of which mounts a sprocket 59 which is engaged by the chaindrive 12 from the prime mover 11. The remaining gear in each clusterengages the gear head on secured to the hub 61 of the clutch wheel 59,the hub 61 being mounted for rotation relative to the sleeve 58 which itsurrounds.

With the arrangement just described, the shaft 13 will remain stationarywhen both clutch wheel 5% and housing 51 are free to rotate, i.e. whenthe clutch bands 52 and 53 are disengaged. However, when the clutch band52 is contracted so as to engage and secure the clutch wheel 50 againstrotation, the sun gear 54 will be rotated in one direction due to theaction of the gear clusters. When, on the other hand, the housing 51 isheld against rotation and the clutch wheel 56) is free to rotate, thegear head 57 will act through the intermediate gear in each cluster todrive the sun gear in the opposite direction. Normally, the clutch wheel50 comprises the down component of the gear system and the rotatablehousing 51 comprises the up component. Thus, when the rotatable housing51 is held against rotation, the lift cable will be wound onto the drum14; whereas when the clutch wheel so is held against rotation, the cablewill be payed out from the drum.

It will be noted from FIGURE 7 that one end of the drum 14 comprises adrum flange 6-2 the periphery of which defines a brake drum 63 coactingwith a brake band 64. The brake band is adapted to enga e the brake drum63 and lock the cable drum 14 against rotation when the clutchcomponents are both released, i.e. when the actuating mechanism is inthe neutral position. However, when the actuating mechanisn1-whichcomprises the cam shaft 19, and the control wheel 26 and the control cam21- is moved to either of the operating positions to thereby engage oneor the other of the clutch bands 52, 53, the brake band 64 will bedisengaged so as to free the cable drum for rotation.

As a practical matter, the clutch bands 52, 53 and the brake band 64 areof identical construction and, as will be evident from FIGURES 5 and 6,are actuated by identical mechanism. Thus, as possibly best seen inFIGURE 6, each of the bands is composed of an upper shoe 65 and a lowershoe 66 each pivoted at one end to the shaft 67 by means of hinges 6-8.At their opposite ends the shoes 65 and 66 mount yoke adapters 69 towhich the yokes 7t and 70a are adju-stably secured. Each pair of yokes70 and 70a is joined together by -a pair of rods 7 ll, '72 provided withsprings '73 surrounding the rods and arranged to urge the yokes towardseach other, thereby clamping the shoes against the drum or wheel withwhich they are associated. Adjustment nuts 74 are provided to vary thecompression of the springs 73 so that the clamping pres sure of the bandmay be adjusted as required. The bands are thus biased toward thecontracted or set position by 'the springs 73 and are expanded orreleased by means of the cams mounted on the cam shaft 19, the camsbeing arranged, upon rotation of the cam shaft 19, to engage the camfollowers 75, 75a mounted on the yokes in the manner seen in FIGURES 5and 6.

The cam followers 75, 75a for each of thebands 52, 55 and 64 arepositioned to engage cams 76, 77 and 73, respectively, mounted on camshaft 19 and rotatable thereby. The brake cam '78 is illustrated inFIGURE 9; whereas FIGURE 10 illustrates one of the clutch cams, such asthe cams 77, the two clutch earns being of identical configuration. Thecam 78 will be positioned on the cam shaft 19 in such fashion that theset of cam followers 75, 75a will lie in the depressions 78a when thecam shaft is in its neutral position; and the clutch cams 76 and 77 willbe arranged in such fashion that the cam followers will be contacted bythe rise portions, such as the pertions 77a, when the cam shaft isrotated to neutral position.

The cam shaft 19 is maintained in its several positions of use by meansof the control cam 21 which, as will be seen in FIGURE 8, is providedwith a pair of spaced apart pockets 79 and 3t adapted to be engaged by acam follower 81 mounted between the arms of a yoke 32, the arms of theyoke each having an elongated slot S3 therein through which the camshaft 19 is arranged to pass, the arms of the yoke lying on oppositesides of the control cam 21. The yoke 82 is secured to an end plate 84of a sleeve 85 which is telescopically received by a second sleeve 86the lowermost end of which is closed by a plate 87 mounting anattachment ear 38. A compression spring 89 is enclosed within thetelescoping sleeves 85 and 86, the spring serving to resiliently biasthe cam follower 81 toward the periphery of the control cam 21. It willbe understood that the attachment car '83 will be secured to a fixedmounting forming a part of the machine frame.

When the control shaft 19 i in its intermediate or neutral position, thecam follower 81 will ride along the intermediate segment 90 of thecontrol cam, but when the cam shaft is rotated, the cam follower 81 willengage one or the other of the pockets 79, 80, thereby securing the camshaft in the rotated position. However, when positive turning force isapplied to the cam shaft, as when the control cable 22 is actuated, theresistance of spring 89 will be overcome and the cam follower 31 will bereleased from the pocket and the control cam 21 will be free to returnto the neutral position.

As should now be apparent, the instant mechanism provides positivecontrol over the operation of the device, the clutch and brake mechanismbeing controlled by movement of the cam shaft 19 which, in turn, isunder the control of the control cable 22. Preferably, the positioningof the clutch cams 76 and 77 relative to the brake cam 78 will be suchthat the selected clutch band will be engaged slightly in advance of therelease of the brake band, thereby assuring that the winch will at alltimes be under the positive control of one or the other of thecomponents. Similarly, the brake band will be set to engage momentarilybefore the release of a given clutch band when the cam shaft is movedfrom the operative to the neutral position. As an added safety factor,it is preferred to provide a centrifugal clutch on the drive shaft ofthe prime mover, particularly where an internal combustion engine isemployed, to control the downward speed of the lift platform underconditions of heavy load. Such clutch will serve as a brake on theengine should it tend to run away under the heavy load.

Modifications may be made in the invention without departing from itsspirit and purpose. For example, if it is desired to control both the upand down move ment of the lift platform, that is, provide adjustablesetting for the lift platform as it travels downwardly from the top ofthe tower, the control cable 22a at the opposite side of the tower couldbe provided with a set of clamps arranged in reverse order to those oncontrol cable 22, i.e. smallest diameter clamp uppermost, and the liftplatform provided with a second cable follower and selector assemblypositioned for engagement by the cable 22a.

Other modifications will undoubtedly occur to the skilled worker in theart upon reading this specification, and consequently I do not intend tolimit the invention excepting in the manner set forth in the claimswhich follow. What I desire to secure and protect by Letters Patent is:

1. In a hoisting machine having a vertical tower along which a liftplatform is raised and lowered by means of a winch and cable, actuatingmechanism for controlling the movement of said winch and cable, saidmechanism comprising clutch means having an up component and a downcomponent operatively connected to said winch, and also brake meansoperatively connected to said winch, the improvement which comprisescontrol means for selectively actuating said brake and clutch means,said control means comprising a rotatable cam shaft mounting a pluralityof cams arranged, upon rotation of cam shaft, to selectively engage andrelease said clutch and brake means, a control cable ex tendingvertically along said tower in alignment with the path of travel in saidlift platform, said control cable being operatively connected to saidcam shaft so that lengthwise movement of said control cable will act torotate said cam shaft, a plurality of cable clamps secured to saidcontrol cable at spaced apart intervals, and control cable engagingmeans associated with said lift platform for selectively engagingpre-determined clamps on said control cable as said lift platform movesup and down along said tower, whereby, upon engagement of apre-determined clamp by said cable engaging means, said control cablewill be moved lengthwise -to thereby actuate said clutch and brakemeans.

2. The device claimed in claim 1 wherein adjacent cable clamps are ofprogressively larger diameter, and wherein said control cable engagingmeans comprises an adjustable selector having a plurality of controlcable receiving openings therein of progressively larger diameter.

3. The device claimed in claim 2 wherein said selec- 'tor comprises arotatable disc, and wherein means are provided to releasably secure saiddisc in predetermined position.

4. The device claimed in claim 3 wherein said selector disc is mountedon a'cable follower having an opening therein of a diameter at least asgreat as the largest opening in said selector disc, and wherein anirregular 'slot opens into the opening in said cable follower, each ofthe openings in said selector disc having a neck portion adapted to bealigned with the said slot to permit which a lift platform is raised andlowered by means of a winch and cable, actuating mechanism forcontrolling the movement of said Winchand cable, said mechanismcomprising clutch means having an up component and .a down componentoperatively connected to said winch,

and also brake means operatively connected to said winch, theimprovement which comprises'control means .for selectively actuatingsaid brake and clutch means,

said control means comprising a rotatable cam shaft mounting a pluralityof cams arranged, upon rotation-of said cam shaft, to selectively engageand release said clutch and brake means, a control wheel at one end ofsaid cam shaft, a control cable extending vertically along said tower inalignment with the path of travel of said lift platform, said controlcable being operatively connected to said control wheel and arranged sothat lengthwise movement of the control cable in either direction willact to rotate said control wheel and the cam shaft on which it ismounted, a plurality of cable clamps secured to said control cable atspaced apart intervals, control cable engaging means associated withsaid 'liftplatform for selectively engaging pre-determined clamps onsaid control cable as said lift platform moves up and down along saidtower, a control cam mounted on said cam shaft, said control cam havinga plurality of spaced apart pockets therein adapted to be selectivelyengaged by a cam follower, depending upon the direction of rotation ofsaid cam shaft, whereby to releasably lock said cam shaft in apre-determined position of use.

6. The device claimed in claim 5 wherein said control cable is anendless cable one portion of which is looped about said control wheeland fixedly secured thereto.

7. The device claimed in claim 6 wherein the cam follower for saidcontrol cam is spring biased toward the periphery of said control cam.

8. The device claimed in claim 7 wherein said control cam has anintermediate or neutral position in which said brake means is set andsaid clutch components are released, said control cam being movable inopposite directions to up and down positions in which said brake meansis released and one or the other of said clutch components engaged,depending upon the direction-of rotation of said control cam, thepockets in said control cam being positioned to releasably retain saidcontrol cam in the up or down positions.

9. In a hoisting machine having a vertical tower along which a liftplatform is raised and lowered by means of a winch and cable, a driveshaft for said winch, clutch means having an up component and a downcomponent operatively connected to said drive shaft, means connectingsaid clutch mechanism to a prime mover, brake means operativelyconnected to said drive shaft, the up and down components of said clutchmeans each having an external clutch drum engageable by coacting pairsof clutch shoes, said brake means including a brake drum engageable bybrake shoes, spring means normally biasing said clutch and brake shoesto drum engaging position, control means for selectively releasing saidclutch and brake shoes, said control means comprising a rotatable camshaft mounting a plurality of cams arranged, upon rotation of cam shaft,to selectively en- .gage and expand said clutch and brake shoes, acontrol cable extending vertically along said tower in alignment withthe path of travel of said lift platform, said control cable beingoperatively connected to said cam shaft so that lengthwise movement ofsaid control cable will act to rotate said cam shaft, a plurality ofcable clamps secured to said control cable at spaced apart intervals,and control cable engaging means associated with said lift platform forselectively engaging pre-determined clamps on said control cable as saidlift platform moves up and down along said tower, whereby, uponengagement of a pre-determined clamp by said cable engaging means, saidcontrol cable will be moved lengthwise to thereby actuate said clutchand brake shoes.

10. The device claimed in claim 9 wherein said cam shaft has anintermediate or neutral position in which said brake shoes are engagedand said clutch shoes are released, said cam shaft being movable inopposite directions to up and down positions in which said brake shoesare released and the said pairs of clutch shoes selectively releaseddepending upon the direction of rotation of said cam shaft.

11. The device claimed in claim 10 wherein the contours of said clutchand brake shoe actuating cams are such that the clutch shoe willibeengaged slightly in ad- 10 vance of the a'elease of said brake shoes,and viceversa, 344,307 Grovan June 22, 1886 whereby said device will beat all times under the positive 1,023,857 Lathrop Apr. 23, 1912 controlof either said brake means or said clutch means- 1,038,020 Sturm Sept.10, 1912 1,586,768 Allen June 1, 1926 References Cited 1n the file ofth1s patent 5 1,599,938 Zetteflund Sept 14, 1926 UNITED STATES PATENTS2,001,674 Erickson May 14, 1935 264,745 Peare Sept. 19, 1882 2,653,685Buck Sept. 29, 1953

1. IN A HOISTING MACHINE HAVING A VERTICAL TOWER ALONG WHICH A LIFT PLATFORM IS RAISED AND LOWERED BY MEANS OF A WINCH AND CABLE, ACTUATING MECHANISM FOR CONTROLLING THE MOVEMENT OF SAID WINCH AND CABLE, SAID MECHANISM COMPRISING CLUTCH MEANS HAVING AN "UP" COMPONENT AND A "DOWN" COMPONENT OPERATIVELY CONNECTED TO SAID WINCH, AND ALSO BRAKE MEANS OPERATIVELY CONNECTED TO SAID WINCH, THE IMPROVEMENT WHICH COMPRISES CONTROL MEANS FOR SELECTIVELY ACTUATING SAID BRAKE AND CLUTCH MEANS, SAID CONTROL MEANS COMPRISING A ROTATABLE CAM SHAFT MOUNTING A PLURALITY OF CAMS ARRANGED, UPON ROTATION OF CAM SHAFT, TO SELECTIVELY ENGAGE AND RELEASE SAID CLUTCH AND BRAKE MEANS, A CONTROL CABLE EXTENDING VERTICALLY ALONG SAID TOWER IN ALIGNMENT WITH THE PATH OF TRAVEL IN SAID LIFT PLATFORM, SAID CONTROL CABLE BEING OPERATIVELY CONNECTED TO SAID CAM SHAFT SO THAT LENGTHWISE MOVEMENT OF SAID CONTROL CABLE WILL ACT TO ROTATE SAID CAM SHAFT, A PLURALITY OF CABLE CLAMPS SECURED TO SAID CONTROL CABLE AT SPACED APART INTERVALS, AND CONTROL CABLE ENGAGING MEANS ASSOCIATED WITH SAID LIFT PLATFORM FOR SELECTIVELY ENGAGING PRE-DETERMINED CLAMPS ON SAID CONTROL CABLE AS SAID LIFT PLATFORM MOVES UP AND DOWN ALONG SAID TOWER, WHEREBY, UPON ENGAGEMENT OF A PRE-DETERMINED CLAMP BY SAID CABLE ENGAGING MEANS, SAID CONTROL CABLE WILL BE MOVED LENGTHWISE TO THEREBY ACTUATE SAID CLUTCH AND BRAKE MEANS. 